CA2615018A1

CA2615018A1 - Device and method for preparing gas mixtures

Info

Publication number: CA2615018A1
Application number: CA002615018A
Authority: CA
Inventors: Klaus Schmidt
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-07-14
Filing date: 2006-06-06
Publication date: 2007-01-18
Also published as: JP4996604B2; US20070017516A1; EP1907038B1; DE102005032977B3; EP1907038A1; WO2007006377A1; JP2009501031A

Abstract

The invention relates to the preparation of gas mixtures, especially respiratory gases for patients needing artificial respiration, and to an associated device and method enabling the application of an additional gas fraction, especially xenon, in a gas mixture, for example, a respiratory gas for patients, in an especially simple manner, with the smallest possible consumption loss of xenon. The inventive preparation involves a respirator (1) comprising an intubation tube (2), a gas mixing chamber (3), and a pressure generator (4). A selection element (5) is provided between the intubation tube and the mixing chamber, for selecting the target fraction of the return respiratory gas from the rest of the fractions or vice versa, in addition to a target supply connection (7) that is connected to a target fraction tank (10) by means of a controlled supply regulator (9).

Description

DEVICE AND METHOD FOR PREPARING GAS MIXTURES
1. Area of application The invention regards the preparation of gas mixtures, in particular of breathing gases for respired patients II. Technical background On demand provision of gas mixtures, wherein a predetermined concentration of single components is maintained, is state of the art.

When the complete gas mix is provided to a user not in a closed, but in an open cycle, and the target-fraction of the gas is partially consumed, and however the remainder of the target-fraction has to be reused or at least collected, this becomes much more complicated, especially depending on the quantities processed and depending on which target fraction relative to the other fractions is being dealt with.

When the target fraction is a noble gas like e.g. Xenon, the handling becomes rather more complicated.

In the medical field it has become apparent, that in particular an induction of Xenon into the breathing cycle of respired patients is helpful for sedating the patient and also for protecting the brain function of the patient.

Gas mixer DE 10 2005 032 977.2-44 The following facts, however make the use of this insight difficult in practice:

- Xenon in the required quantities is rather expensive at a cost of US$ 15 per liter and a consumption of 6 liters per respiration minute per patient and - due to cost pressures the acquisition of new respiration equipment allowing the provision of Xenon is delayed III. Description of the invention a) Technical Objective Therefore the objective of the invention is to provide a device and a process, al-lowing the provision of an additional gas fraction, xenon in particular, within a gas mix, e.g. a breathing gas for a patient, in a very simple manner an with usage losses of xenon as small as possible.

b) Solution This objective is accomplished through the features of the claims 1, 15 and 16.
Preferred embodiments can be derived from the dependent claims.

Through an adjustable supply regulator for the target fraction for preparing the breathing gas, the percentage of the target fraction, e.g. Xenon, in the breathing gas can be adjusted exactly according to requirements.

In case the remainder of the breathing gas did not yet contain xenon, since it was e.g. made from ambient air with the addition of oxygen, also no sensor for meas-uring the prior content of the target fraction is necessary.

2 Gas mixer DE 10 2005 032 977.2-44 If however the breathing return gas exhaled by the patient is to be recycled and reused as a breathing gas, if necessary through the addition of fresh oxygen, the percentage of the target fraction already contained in the return gas has to be measured through a sensor and has to be considered when adding the target frac-tion.

Independently from the above, in the path of the breathing return gas, between the intubation-hose and either the open outlet for the breathing return gas or the return into the gas mixing chamber for preparing the new breathing gas, a selec-tion element is present for reusing the target fraction:

This can be an active separator, separating the target fraction form the rest of the gas mix, if the return gas shall be released into the atmosphere. This could be a centrifuge, or a simple membrane, which lets all other components of the return gas pass into the environment, but not the target fraction.

If the breathing return gas is recycled and used for producing fresh breathing gas, the target fraction included in the breathing return gas can be kept there, but for processing the breathing gas new and other fractions than the target fraction have to be added to (e.g. oxygen) or extracted from the breathing return gas (e.g.
car-bon dioxide).

Also here it has to be assured that when adding or subtracting other fractions, the target fraction is not subtracted unintentionally.
This can be performed through a passive selector e.g. a membrane, through which other fractions than the target fraction ca enter or exit the mixing chamber, but the target fraction cannot exit.

In this case, when recycling the breathing return gas for producing new breathing gas, the content of the target fraction in the breathing return gas or after process-

3 Gas mixer DE 10 2005 032 977.2-44 ing the new breathing gas, but before adding fresh target fraction, has to be known and therefore has to be measured by a sensor.

The target supply connection is then controlled depending on the results of the sensor, preferably through an electric or electronic controller, which is preferably connected with the control system of the rest of the breathing apparatus, or even integrated into it.

If the target fraction is not actively separated from the rest of the breathing gas, a target exhaust connection for exhausting the mixture including the target fraction is provided in the part of the gas path, connected with the reservoir and / or the supply regulator for the target fraction, where preferably the sensor for the deter-mination of the target fraction is located.

Thereby a separation of the target fraction form the remaining fraction is not nec-essary and only the required additional quantity of target fraction is inducted into the path of the gas mix, e.g. in a mixing chamber, which is therefore provided.

For this a bypass to the main gas path can be provided through the target supply and target exhaust connection, which is used for adding additional target fraction, being connected with the reservoir of the target fraction.

In case the remaining gas mix is not processed again, but released into the envi-ronment (open cycle of the main gas mix), on the side of the target supply and target exhaust opposite from the point of consumption a selection element, e.g. a selective membrane, which passes all fractions, besides the target fraction is nec-essary.

In case the main gas mix is recycled and reprocessed, such a selection element may not be necessary, e.g. when

4 . CA 02615018 2008-01-11 Gas mixer DE 10 2005 032 977.2-44 - no fractions have to be removed from the breathing return gas during the reprocessing and - fresh quantities added into the return gas are added e.g. through valves allowing passage into the gas cycle only in supply direction.

In order to provide a retrofitable ad on device for a conventional gas processing device like a respirator it is possible, in particular with recirculated breathing gas, and also with a closed cycle of the target fraction or of the gas mix including the target fraction, to provide sensor, supply regulator and also the supply connection for the reservoir of the target fraction connected with the supply regulator and a possibly not necessary pressure generator for the target fraction in a target con-troller as an integrated subassembly, which can be integrated into the gas path of the processor, e.g. forming a bypass conduit.
In case a selection unit is necessary, preferably also this selection unit, e.g. a se-lective membrane is located in the adapter, or in the target control unit.

In case of a y-shaped gas path this can be in the branch between the y-spot and the consumer, this means the patient, but also in the divided branches for exhala-tion and inhalation, wherein the target supply connection is located at (east in the inhalation branch.

c) Embodiments Embodiments of the invention are subsequently described as examples in more detail. It is shown in:

FIG. 1: a principle schematic of the process FIG. 2: several general ways to solve the problem and

5 Gas mixer DE 10 2005 032 977.2-44 FIG. 3: detailed embodiments according to the invention.

FIG. 1 shows in principle, how in a mixing chamber (3) a gas mix is generated from several base components (A, B, C) and via a conduit, in this case a intuba-tion hose (2), supplied to a consumer e.g. the patient. Therefore a pressure gen-erator (4), e.g. a blower is integrated into the conduit. Into this conduit an addi-tional target component (Z) shall be provided via the target supply connector (7), which is performed from the reservoir (10) via the supply connector (7) via a ad-justable supply regulator (9).

The gas mix hereby is not only provided to the consumer through the conduit (2), but also the unused rest, this means the breathing return gas, is also returned again towards the mixing chamber (3).
In order not to loose the target fraction (Z) contained in the breathing return gas into the mixing chamber (3) and from there through the component supply lines to the outside, a selection element (5) is required in the path of the gas.

This can be an active separation device for separating the component (Z) from the gas mixture, whereby the target component (Z) can be returned into the reservoir or be reused otherwise. This can also only be a passive barrier, avoiding the reflux of the target component into the component inflows (A, B, C).

As shown in FIG. 2, for this purpose the target component (Z) can be provided, preferably directly into the mixing chamber, into the mixture out of the reservoir (10), preferably again through pressurization with a pressure generator (4) be-tween the reservoir (10) and the supply connection (7).

The content of target fraction in the gas mixture can be measured either in the mixing chamber (3) or in the supply line, e.g. the intubation hose (2) to the mixing ciiairiber or also tf-iruugii extractirig the complete mixture via a target exhaust con-

6 Gas mixer DE 10 2005 032 977.2-44 nection (8) and supplying it again through a bypass to the supply connection

(7) after replenishing additional target component (Z) from the reservoir (10), wherein before the supply the target fraction (Z) content is measured in the bypass through a sensor (6).
The supply connections for the additional components (A, B, C), which need to be partially added to the return gas in addition, also lead into the mixing chamber (3).
An outflow of the target fraction (Z) through these supply connections (A, B, C) is avoided, either through them being located behind a membrane (12), which is not permeable for the component (Z), or by providing the components (A, B, C) in a manner, that they can only be passed in supply direction into the gas mixing chamber (3), no matter by which fraction.

FIG. 2b on the other hand shows a solution, where the mixing chamber has a membrane (12), which is only permeable for the target fraction (Z) and which is impermeable for the other components (A, B, C).

Accordingly the target supply connection (7), which is connected with the target feed connection (13) and in particular with the reservoir (10), is located in the mix-ing chamber on the opposite side from the outlet, this means on the side of the membrane (12') opposing the intubation hose (2), while the connections (A, B, C) for the other components are located on the same side of the membrane as the outlet connection.

FIG. 2c shows a solution, where the inspiration path (17) and the expiration path (18) with their respective hoses run separate from the Y-piece (16), preferably with a flap for selectively opening one of the two hoses towards the central piece, the intubation hose.

In the embodiment in FIG. 2c, from the expiration hose (18) a separation of the target fraction (Z) is performed through a membrane (12'), while the remainder of the breathing return gas is either released into tI'le ei Ivirotlrrlent, then however Gas mixer DE 10 2005 032 977.2-44 through a membrane (12) impermeable for the Z-fraction, or recirculated and pro-vided to the gas mixing chamber (3) for preparing fresh breathing gas, whereby the membrane (12) is not necessary.

Into the mixing chamber for the fresh breathing gas additional target fraction (Z) is provided from a reservoir (10) though an adjustable supply regulator (9), whereby a pressure generator (4') may be necessary in this supply line.

Into the reservoir (10) also the target fraction (Z) extracted from the expiration path (17) can be fed, wherein it's cleaning device (21) is located in this return path.

In this case the breathing gas or the breathing return gas is selectively run in an open or in a closed cycle, and also the separated target fraction (Z) is selectively run in a closed cycle, or recycled in spite of an open cycle.
The Figures 3 show a defined application of an applicator unit (20), which can be retrofitted on a conventional respirator (1), which respires a patient via a Y-piece (16) and via an intubation hose (2) Thereby a closed cycle of the breathing gas or the breathing return gas is as-sumed, wherein for processing breathing gas from the return gas supplemental oxygen is added via an adjustable supply regulator (9) and, - what is not shown here - also C02 is extracted where necessary According to FIG. 3a the applicator unit (20) is located between the intubation hose (2) and the Y-piece (16). The applicator unit (20) comprises a target adapter (15), which is located between the intubation hose (2) and the Y-piece (16) and from which a bypass (11) branches off analogous to the schematic in FIG. 2a, this means with a sensor (6) for measuring the content of the target fraction in the gas mix, a supply of target fraction through an adjustable supply regulator (9) from a target fraction reservoir (10) and if necessary with pressurization via a pressure generator (4') located in the bypass coriduit.

8 Gas mixer DE 10 2005 032 977.2-44 The supply regulator (9) is controlled by the control system (19), receiving signals form the sensor (6) and preferably connected with the control system (19') of the respirator (1), or even integrated into it.
The membrane (12) drawn between the inlet- and outlet connections (7) and (8) for the target fraction (Z) and the Y - piece (16), which is permeable for all frac-tions besides the target fraction, prevents an inflow of the target fraction into the remaining cycle of the breathing gas. This is only necessary, in case the other inlets and outlets of this cycle would allow an outflow of the Z-component from the cycle. If this is prevented through special inlet valves, e.g. for the oxygen, the membrane (12) can be omitted.

FIG. 3b shows a solution, wherein the target supply connection (7) and the target outflow connection (8) for the target component (Z) are located on the side of the Y-connection (16) pointing away from the patient, in the expiration conduit (18) of the target outlet connection (8) and in the inspiration conduit (17) of the target supply connection (7), when the target connection (Z) together with the rest is also here run in the bypass conduit (11) in a closed loop.
Also here in each of them a membrane (12) or (12') is required, in case the rest of the cycle of the breathing gas, e.g. the in feed for the oxygen does not prevent the outflow of the target fraction by design. If this is the case, the membranes (12), (12') can also be omitted here.
Then it can also be possible to leave the target outlet connection (8) out com-pletely, if the sensor (6) is instead located directly in the cycle of the breathing gas, preferably directly in front of the target supply connection (7).

The target supply connection (7) is then connected with the reservoir (10) only via the adjustable supply regulator (9).

9 Gas rnixer DE 10 2005 032 977.2-44 Reference numerals 1 Respirator 2 Intubation tube 3 Gas miixing chamber 4, 4' Pressure generator 5 Selection element 6 Sensor 7 Target supply connection 8 Target outlet cnnection 9 Supply regulator

10 Reservoir

11 Bypass 11 a, b Bypass conduits

12, 12' Membrane

13 Target feed connection

14 Target control system

15 Target adapter

16 Y - piece

17 Inspiration hose

18 Exspiration hose

19 Controller

20 Applicator unit

21 Purging device

Claims

1. A respirator (1) with - an intubation hose (2), - a gas mixing chamber (3) and a pressure generator (4), characterized in, that - between the intubation hose (2) and the mixing chamber (3) a selection ele-ment (5) with respect to the target fraction (Z) of the breathing return gas and it's remaining fractions (rest), or versa, is provided and - a target supply connection (7), connected with a controlled supply regulator (9) and with a supply fraction reservoir (10).

2. A respirator (1) according to claim 1, characterized in, that - at least one sensor (6) for measuring the concentration of the target fraction (Z) ins provided in the gas path of the breathing gas of the respirator and - the sensor (6) controls the supply regulator (9).

3. A respirator (1) according to one of the preceding claims, characterized in, that the selection element (5) is an active separation device for separating the target fraction (Z) from the remaining fractions (rest) of the breathing return gas.

4. A respirator (1) according to one of the preceding claims, characterized in, that the selection element (5) is a passive selective barrier, a membrane in particular, with a different permeability for the target fraction on the one hand and for the re-maining fractions of the gas mix on the other hand, possibly depending on the di-rection of passage.

Gas mixer DE 10 2005 032 977 2-44

5. A respirator (1) according to one of the preceding claims, characterized in, that a pressure generator (4') is connected with the target supply connection (7) (closed loop)

6. A respirator (1) according to one of the preceding claims, characterized in, that a target outlet connection (8) is provided in the section of the gas path of the breathing gas connected with the reservoir (10) and / or the supply regulator (9), in particular containing the sensor (6), whereby a bypass (11) connected with the reservoir (10), in particular for the complete mix is provided.

7. A respirator (1) according to one of the preceding claims, characterized in, that the selective membrane (12), in particular in both directions, is only permeable for the target fraction (Z), but not for the other fractions of the gas mix, and wherein the target outlet connection (8) is located on the clean target fraction side of the membrane (12). (planned solution)

8. A respirator (1) according to one of the preceding claims, characterized in, that the membrane (12) is permeable for all other fractions besides the target fraction (Z) of the gas mix, and this property being pertinent for both flow directions of the membrane and the supply connection (7) and the outlet connection (8) originating on the target connection side of the membrane (12).

9. A respirator (1) according to one of the preceding claims, characterized in, that the sensor (6), the regulator (9) and at least the target feed connection (13) for the reservoir (10), in particular including the reservoir (10), possibly also a target pres-sure generator (4'), are located in a target control unit (14) as an integrated unit, connectable via the bypass conduits (1/a, b) with the respirator (1).

10. A respirator (1) according to one of the preceding claims, characterized in, that the respirator (1) comprises a target adapter (15) in the gas path for connecting the target control unit (14), comprising the selection element (5), in particular the membrane (12), and which can be inserted as a connector between the intubation hose (2) and the gas mixing chamber (3), with a Y-shaped path in particular downstream of the Y-piece (16) in the intubation hose (2).

11. Respirator (1) according to one of the preceding claims, characterized in, that the target adapter (15) together with the bypass conduits (11 a, b) and the target control unit (14) forms a uniform and in particular retrofitable applicator-unit (20)

12. Respirator (1) according to one of the preceding claims, characterized in, that the supply regulator (9) and possibly the sensor (6) are coupled with an, in particu-lar electric or electronic, control system (19), which are jointly capable to maintain a constant concentration of the target fraction (Z) in the mixture of the breathing gas.

13. Respirator (1) according to one of the preceding claims, characterized in, that the target fraction (Z) is a noble gas, in particular xenon.

14. Respirator (1) according to one of the preceding claims, characterized in, that the control system (19) for the target fraction (Z) is coupled with the control system (19') of the respirator (1), and integrated into it in particular.

15. A process for recovering and mixing a target gas fraction in a gas mixture characterized in, that - the gas mix is run by the consumer in a closed loop, which partially con-sumes at least the target gas fraction.
- the concentration of the target gas fraction in the mixture is measured at least at one location in the loop, in particular measured continuously, and - through comparing the target-concentration with the actual concentration the supply of additional target concentration is controlled.

16. Process according to claim 15, characterized in, that the measurement of the actual concentration of the target fraction is performed directly after the consumer.

17. Process according to one of the preceding process claims, characterized in, that the measurement of the actual concentration of the target gas fraction is per-formed in a bypass for extracting the mixture and supplying the mixture with the added target fraction from the main loop.

18. Process for reusing and additively mixing a target gas fraction in a gas mix-ture, characterized in, that the gas mix is run in an open cycle and the target gas fraction is separated from the rest of the mix before the end of the cycle and supplied to the target gas res-ervoir for target gas provision with a time delay in particular due to recycling and compressing.